Parasitic helminth infection protective

The remarkable success that has been achieved with identification of protective, recombinant antigens against the Taenia and Echinococcus species has been in stark contrast to the general lack of success that has been achieved with vaccine development against other parasitic helminth infections (Dalton and Mulcahy, 2001). Hence, very little direction has been available from the experiences of others on how to translate a laboratory success with an anti-parasite vaccine into a practical (commercial) vaccine. First principles would suggest a host of issues that require investigation/opti-mization, for example ... 

This report will detail current knowledge of the role of IgE in mediating immunity to helminth parasites. Because IgE responses to helminth infections differ based on chronicity of infection, the life cycle of the parasite, and the parasite s location within the host, it is difficult to apply data from one parasite to those of another, particularly in theorizing about the potential effects of anti-IgE therapy. The report will focus, in particular, on schistosomiasis and strongyloidiasis, for which most observational and experimental data have been accumulated to support a protective role for IgE. The latter infection is of particular relevance because of its unusual capacity to replicate within the human host, so-called auto-infection. Although most of the discussion will rely on data from human studies, much of this information is incomplete, and, where appropriate, observations from experimental animal models will be included. 

Rodriguez-Sosa, M., Rosas, L.E., David, J.R., Bojalil, R., Satoskar, A.R. and Terrazas, L.l. (2003b) Macrophage migration inhibitory factor plays a critical role in mediating protection against the helminth parasite Taenia crassiceps. Infection and Immunity 71, 1247-1254. 

Applying the protective role of parasite infection against inflammatory disorders, over the years a wide range of helminths and their derived products have been associated with the potential to modulate autoimmunity and allergic disorder, approaching the therapeutic wiudow. 

Intestinal helminths have been used as the prototypical parasite infections to demonstrate the importance of IgE in mediating protection. Indeed, it has been demonstrated that passive transfer of IgE antibodies can mediate the rapid expulsion phenomenon in rats infected with T. spiralis (89) and that diminished levels of IgE are associated with dissemination of Strongyloides stercoralis (61,90) in the context of HTLV-I coinfection. With the elucidation of the cytokine control of the IgE response (e.g., IL-4 and IL-13), however, and the fact the these cytokine responses exist in the context of a broader (Th2 or Type 2) response, the IgE response itself may be merely an indicator of a more general response, whose many different components effect the protective response (reviewed in Refs. 91-94). 

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